Usain Bolt of Jamaica celebrates after winning gold. [Photo/Agencies]

RIO DE JANEIRO - After his Olympic sprint double at the London 2012 Games, Usain Bolt declared himself a "legend". After winning both events for a third time he opted for "the greatest".

The 29-year-old Jamaican eased to 200 meter gold in 19.78 seconds in Rio on Thursday to take his tally to eight sprint Olympic golds following Sunday's 100m success in Rio.

"There's nothing else I can do really," said Bolt, who became the first athlete to win the two individual sprint titles in three consecutive Olympics.

"I've proven to the world that I'm the greatest and that is what I came here for and that's what I'm doing.

"This is what I worked for throughout the years. I worked to be the best, to be among the greats."

The Jamaican had made positive noises about an assault on his own 2009 world record of 19.19 but instead his winning time on a chill, damp night was the slowest of his seven world and Olympic 200m victories.